12-04-2010 06:53 AM #1
comp cam noise
ive been interested in the cc xe256h cam so i googled it and noyiced alot of people talking about it creating a noisy valvetrain.Is this just talk or something to it? can it be harmful to my motor ? I would think that comp would have realized this during their engineering research. I really like the numbers on this cam but am starting to shy away from it.
Last edited by blumule; 12-04-2010 at 11:01 AM.
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I have a Comp Cam XE roller in my 383. It sounds like I have a solid cam. Called Comp , they sent me another set of lifters. Noise was the same. Replaced them with GM lifters. Noise is the same. If I wanted the sound of a solid cam I would have bought a solid lift cam. I'm replacing it with a LT hot cam or a Voodoo 60121.
As I've posted previously, in my 331 sbf, I'm running a Ford Racing X303 cam, Ford Racing roller rockers, and Harlan Sharp roller rockers. It is the noisiest motor I've ever owned or heard.........ticks like mad. When I tear it down I am going to do some serious research to find out whats what. Strange to hear you other guys are having noise issues and questions too.
It's the xe (Xtreme Energy) part of the cam that's producing the problem. The ramps on those grinds are just this side of letting the edge of the lifter dig into the lobe. Change to a Magnum grind and the rattle should go away.
You can tell whether a cam is ground on the extreme pattern or not by subtracting the 0.050" duration from the advertised (0.006") duration. Anything 50 degrees or more (280/230 for instance) should be ok. Crane, I remember, used to grind all their cams with a 56 degrees difference.
The XE256H is 212/256 on the intake, a difference of only 44 degrees.
I have a roller cam. The tech guy at Comp told me it was beacause the opening & closing rate of the cam is slamming the valves closed. Makes no sense to me.
With any given amount of duration, the quicker you can get the valve open and the quicker you can get it closed, the longer time you have to pass fuel/air mixture through it and the more power you will make.
I know why they designed it, but I would not have put on the market knowing it made noise. I even removed the engine, disassembled it, & checked everything. Had to buy new gaskets & rings. Then I called Comp cams & they sent me the lifters. Another intake gasket & oil change. Then I bought the GM lifters. Not cheap. Also another intake gasket & oil change. All total I have spent close to $600.00 chasing a noise that Comp Cams knew about.